Offshore oil and gas well drilling rig

ABSTRACT

An offshore drilling platform and drilling rig mounted thereon having a load boom assembly and a balance boom assembly mounted for pivotal movement on the derrick of the drilling rig. The boom assemblies are erected into load bearing position to move loads about the platform.

United States Patent [191 Levingston Aug. 14, 1973 OFFSHORE OIL AND GASWELL DRILLING RIG [75] inventor: Clarence W. Levingston, Orange,

Tex.

[73] Assignee: Levingston Shipbuilding Company,

Orange, Tex.

22 Filed: Feb. 1, 1972 [21] Appl. No.: 222,586

[52] US. Cl 212/47, 212/48, 212/46 R [51] Int. Cl. B66c 23/00 [58] Fieldof Search 212/47, 48, 49, 56,

212/58, 46 R, 46 A, 46 B, 57, 64; 214/25; 175/85 [56] References CitedUNITED STATES PATENTS 7/1960 Guier 2l4/2.5 11/1950 Woolslayer et a1.214/2.5 4/1954 Favre et a1. 212/46 R FOREIGN PATENTS OR APPLICATIONS635,162 2/1962 Italy 212/64 558,318 6/1957 Belgium 212/64 1,093,67912/1967 Great Britain 212/64 1,183,609 3/1970 Great Britain 212/46Primary Examiner-Even C. Blunk Assistant Examiner- Merle F. MaffeiAttorney-Paul E. Harris. Lee R. Larkin and Larry B. Phillips et a1.

[57] ABSTRACT 2 Claims, 6 Drawing Figures minnows 14 ms 3 752' 32s sum 1OF 3 PATENTS!) NR 14 813 SHEET 2 0F 3 .liimh.

PAIENTED MN; I 4 I973 SHEET 3 OF 3 OFFSHORE OIL AND GAS WELL DRILLINGRIG BACKGROUND OF THE INVENTION 1. Field of the Invention The field ofthe invention is offshore drilling rigs and methods for their use.

2. Description of the Prior Art As is well known in the art of drillingoffshore oil and gas wells, the process of erecting a drilling platformover an offshore drilling site is an expensive and time consuming one.It has been found to be particularly advantageous to elevate thedrilling platform above the surface of the body of water under which thewell is to be drilled. Elevating the platform above the surface of thewater reduces lateral stresses on the structure from wave action.

Problems have been experienced, however, with towing such rigs from portto the drilling site. With spuds as long as 400 feet carried in a raisedposition above the drilling platform, the rigs tend to be unstable inthe floating state. Attempts have been made to solve this problem bytransporting the drilling rig with the spuds disassembled and carried ontop of the drilling platform or on another vessel, but this necessitatesthe use of a derrick barge or the construction of one or more cranes onthe structure of the platform itself to assist in assembling the spuds.The use of derrick barges and the construction of cranes on the platformis a source of great expense, but they have been widely used to avoidthe problem of instability while the rigs are being transported from onelocation to another.

SUMMARY OF THE INVENTION The inventive concept is the improvement inoffshore oil and gas well drilling rigs which lies in the combination ofthe drilling derrick with a load boom assembly and a balance boomassembly. The load boom and balance boom are mounted on the derrick ofthe rig for pivotal movement in a vertical plane containing the longaxis of the mast and for rotation about the long axis of the mast.

The method of the invention includes the steps of erecting the load boomand balance boom and moving loads about the drilling platform onto andfrom another vessel with the load boom.

The combination of the load and balance boom assemblies with an offshoredrilling derrick provides a structure for moving large loads about thedrilling platform without the inconvenience and expense of additionalcranes or use of a derrick barge with a crane thereon alongside theplatform.

BRIEF DESCRIPTION OF THE DRAWINGS The inventors presently preferredembodiment of the invention is shown in the drawings, in which:

FIG. 1 is a side elevation view of the novel offshore oil and gas welldrilling rig which includes a showing of the load boom assembly andbalance boom assembly in the load-lifting attitude.

FIG. 2 is a side elevation view of the drilling platform in the drillingattitude, showing one spud of the plat form and showing the load boomand balance boom folded into the stowed position.

FIG. 3 is a top sectional view of the novel offshore oil and gas welldrilling rig which includes a taken along line 3-3 of FIG. 1, showingthe load boom and balance boom in the working position.

FIG. 4 is a side elevation sectional view of the boom support bearingwhich allows rotation of the load boom and balance boom about the longaxis of the mast.

FIG. 5 is a side elevation view partially in section of the load sheaveblock in the load boom assembly.

FIG. 6 is a generally schematic side elevation view of the load sheaveblock of the load boom assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT The inventors presentlypreferred embodiment of the invention is shown in FIG. 1. The structuregenerally designated by the numeral 10 is the drilling derrick, or mast,supported by an offshore platform, generally designated by the numeral11. The drilling derrick is shown in the load-moving configuration, withthe balance boom 12 and the load boom 13 extended therefrom. Balanceboom 12 is suspended by balance boom cable 14 and load boom 13 issuspended by load boom cables 15. Balance boom 12 and load boom 13 areraised to operating position, or lowered to stowed position by thelifting cables 73 and 74 and an auxiliary winch 17. Lifting cable 73passes over balance boom topping lift 16 and down through derrick 10 toauxiliary winch 17. Similary, load boom 13 is raised or lowered bylifting cable 74 passing over the load boom topping lift 19, downwardlythrough derrick 10 and secured to auxiliary winch 17. Balance boom 12supports a balancing load 29 for counteracting the force moment of aload 26 to be lifted by load boom 13.

Balancing load 29 may take the form of a tank containing water toprovide a variable counteracting moment.

Balance boom 12 is joined to derrick 10 for both vertical pivotalmovement and horizontal pivotal movement with respect to derrick 10.Means connecting balance boom 12 to derrick 10 for vertical pivotalmovement takes the form of balance boom pivot 18 and lifting cable 73.Disconnecting cable 14 and activating auxiliary winch 17 to let outlifting cable 73 will result in balance boom 12 descending to thefolded, or stowed, position, as shown in FIG. 2. It is contemplated thatauxiliary winch 17 also will similarly control the attitude of load boom13. Therefore, disconnecting cable 15 and letting out cable 74 byauxiliary winch 17 would result in a similar lowering of load boom 13 tothe folded, or stowed, position, as shown in FIG. 2. The numeral 20refers to the drawworks winch which is utilized in the drilling attitudefor connecting the travelling block 51 to the crown block 50, as shownin FIG. 2 and as will be further described hereafter. Drawworks winch 20is used in the load lifting attitude as the power source for liftingloads with load boom assembly 13. In the load-lifting attitude,drawworks winch 20 is connected to the drawworks line 21, which line isthreaded through a series of pulleys 22, 23 and 24 and passes to theload sheave block 25. Thus, winding drawworks line 21 about drawworkswinch 20 will result in shortening of drawworks line 21 and lifting ofload 26 thereby. For purposes of illustration, load 26 takes the form ofa section of spud 27. In this illustration, sections 26 of spud 27 maybe lifted from platform 11 or from another vessel, moved to a positionof spud 27 and lowered into mating engagement therewith.

In the embodiment shown in FIG. 1, derrick 10 includes a lower portion30 and an upper portion 31. Upper portion 31 supports balance boom pivot18 and a load boom pivot 28 which provide vertical pivotal movement forthose booms. Upper section 31 may also be rotated about its long axiswith respect to lower section 30, thereby rotating balance boom 12 andload boom 13 therewith. Pivots 18, 28 may also be supported from aunitary derrick (not shown) with suitable bearings (not shown) arrangedto allow for rotation of load boom 13 and balance boom 12 about derrick10. In FIG. 1, support for upper section 31 is provided by annularbearing 40, detail of which is shown in FIG. 4. Annular bearing 40includes an inner annular member 41 surrounded by an outer annularmember 42. Inner annular member 41 may be supported by lower section 30of derrick and outer annular member 42 supports upper section 13.interposed between inner member 41 and outer member 42 is a roller 43 toprovide for relative rotation of inner member 41 and outer member 42.

As shown in FIG. 3, upper section 31 is supported at its lowermostportion by a pivot housing 32. Pivot housing 32 includes means forrotating upper section 31 with balance boom 12 and load boom 13 aboutthe long axis of derrick 10 relative to lower section 30. The means forrotating includes annular bearing 40 and a pivot drive wheel 33supported by lower section 30 which may be rotated by any convenientdrive means (not shown). As pivot drive wheel 33 is rotated, itsarrangement in contact with outer annular member 42 will impart rotationto upper section 31 relative to lower section 30.

FIG. 2 shows derrick 10 in the drilling attitude. Drawworks winchengages drawworks line 21 as in FIG. 1; but in FIG. 2, drawworks line 21is led through crown block 50 and traveling block 51 to support a swivel52, a kelley 53 and string of drill pipe 54. In the drilling attitude,as shown in FIG. 2, derrick 10 functions as any other derrick in thedrilling art, supporting the string of drill pipe 54 during drillingoperations. Auxiliary winch 17 may be utilized for any function normallyassociated with such devices during drilling procedures, such aslowering well tools (not shown) down the wellbore.

FIG-6 shows schematically the load sheave block generally designated bythe numeral in FIG. 1. Load sheave block 25 includes means for moving aload radially of the longitudinal axis of derrick 10, which meansincludes radial positioning line 60 in the form of a continuous closedloop supported by a positioning line pulley 61 at one end of the loopwith the other end of the loop wrapped on a power driven drum (notshown). Drawworks line 21 is shown in the load supporting attitude,threaded through load pulley 62, 63, 64. The arrow directed downwardlyfrom load pulley 63 indicates the direction of force of a load suspendedfrom load sheave block 25. Load sheave brackets 65, 66 support loadpulleys 62, 64 respectively. Support wheels 67, 68 support load sheavebracket 65 and, in the same manner, support wheel 69, 70 support loadsheave bracket 66 and provide means for radial movement of load sheaveblock 25 along support beams 71, 72, as shown in FIG. 5. In FIG. 6, loadsheave block 25 is driven to the left or right, as shown in FIG. 6, bythe force imparted to positioning line 60 by the power driven drum (notshown).

An alternate method of moving the load radially to the long axis of themast or derrick, is to use lifting line 74 extended over load boomtopping lift 19 and connected to auxiliary winch 17 to raise and lowerthe outer end of load boom 13.

The inventor's presently preferred embodiment of the method of theinvention includes errecting load boom assembly 13 and balance boomassembly 12 on derrick 10 to the load-lifting attitude, as shown inFIG. 1. Thereafter, a load, such as spud section 26, is suspended fromload boom assembly 13 and moved to a position adjacent the top of spud27. Spud section 26 is then attached to the upper portion of spud 27.Spud 27 may then be extended downwardly through platform 1 l and othersections added until the sea bottom is contacted and platform 11 isjacked up above the surface 34 of the water.

Additionally, the inventors presently preferred embodiment of theapparatus can be utilized on a drilling platform to move heavy objects,such as blow-out preventer stacks, well heads and machinery packages.

Also, it can be used for setting well structures supporting the wellhead independent of the drilling platform, and for carrying out piledriving operations.

Thus it can be seen that an improved apparatus and method for its use inconnection with drilling an offshore well has been shown. Furthermodifications and alternative embodiments of the invention will beapparent to those skilled in the art in view of this description.Accordingly, this description is to be construed as illustrative onlyand is for the purpose of teaching those skilled in the art the mannerof carrying out the invention. It is to be understood that the form ofthe invention herewith shown and described is to be taken as thepresently preferred embodiment. Various changes may be made in theshape, size and arrangement of parts.

For example, equivalent elements or materials may be substituted forthose illustrated and described herein, parts may be reversed andcertain features of the invention may be utilized independently of theuse of other features, all as would be apparent to one skilled in theart after having the benefit of this description of the invention.

I claim: 1. An offshore oil and gas well drilling rig comprising, incombination an offshore drilling platform a drilling mast supported bysaid offshore drilling platform and having an upper section and a lowersection the upper section of said drilling mast being rotatably disposedon the lower section thereof a draw-works including a draw-works winchand an auxiliary winch disposed on said offshore platform at the foot ofthe lower section of said drilling mast a crown block mounted on theupper portion of said drilling mast adjacent the top thereof a pair ofpivot supports secured to the lower end of the upper section of saiddrilling mast and oppositely disposed with respect to one another a loadboom having its inner end pivotally connected to one of said pivotsupports a balance boom having its inner end pivotally connected to theother of said pivot supports a load sheave block carried by said loadboom a suitably operated positioning line connected to said load sheaveblock for horizontally moving the latter along said load boom a loadboom topping lift mounted adjacent the upper extremity of the uppersection of said drilling mast 6 a lifting cable connected to said loadboom, trained works winch over said load boom topping lift, and directedsaid draw-works line being passed around said crown downwardly throughsaid drilling mast for attachblock and downwardly through said drillingmast to ment to said auxiliary winch carry a travelling block, swiveland kelly or alternaa balance boom topping lift mounted adjacent the 5tively upper extremity of the upper section of said drilling saiddraw-works line being directly attached to said mast load sheave blockfor raising and lowering the load a lifting cable connected to saidbalance boom, carried thereby.

trained over said balance boom topping lift, and di- 2. The combinationof claim 1 wherein the pivotally rected downwardly through said drillingmast for 10 mounted load boom and balance boom are movable attachment tosaid auxiliary winch and between full horizontal and full verticalpositions. a draw-works line connected at one end to said draw-

1. An offshore oil and gas well drilling rig comprising, in combinationan offshore drilling platform a drilling mast supported by said offshoredrilling platform and having an upper section and a lower section theupper section of said drilling mast being rotatably disposed on thelower section thereof a draw-works including a draw-works winch and anauxiliary winch disposed on said offshore platform at the foot of thelower section of said drilling mast a crown block mounted on the upperportion of said drilling mast adjacent the top thereof a pair of pivotsupports secured to the lower end of the upper section of said drillingmast and oppositely disposed with respect to one another a load boomhaving its inner end pivotally connected to one of said pivot supports abalance boom having its inner end pivotally connected to the other ofsaid pivot supports a load sheave block carried by said load boom asuitably operated positioning line connected to said load sheave blockfor horizontally moving the latter along said load boom a load boomtopping lift mounted adjacent the upper extremity of the upper sectionof said drilling mast a lifting cable connected to said load boom,trained over said load boom topping lift, and directed downwardlythrough said drilling mast for attachment to said auxiliary winch abalance boom topping lift mounted adjacent the upper extremity of theupper section of said drilling mast a lifting cable connected to saidbalance boom, trained over said balance boom topping lift, and directeddownwardly through said drilling mast for attachment to said auxiliarywinch and a draw-works line connected at one end to said draw-workswinch said draw-works line being passed around said crown block anddownwardly through said drilling mast to carry a travelling block,swivel and kelly or alternatively said draw-works line being directlyattached to said load sheave block for raising and lowering the loadcarried thereby.
 2. The combination of claim 1 wherein the pivotallymounted load boom and balance boom are movable between full horizontaland full vertical positions.